Organic silicon compound is generated when silicon powder reacts with chloromethane with the action of catalyst. Organic silicon is not only a kind of new-style material itself, but also provides a new material base and technical guarantee for the development of relevant industry fields. High development speed is always kept in organic silicon industry, the yield of organic silicon (converting into siloxane) in China was up to 200 kt/a in 2006.
The gas mixture generated from the reaction of silicon powder and chloromethane with the action of catalyst is a kind of mixture that contains several kinds of silane gas and dusty raw material. It needs to remove dust from gas mixture during the production of organic silicon.
Currently, dry and wet dust removal equipment is mainly used in organic silicon plant, namely, several sets of serial cyclone separator dust-removal systems and venturi dust-removing system are used to effectively separate solid dust from the gas-phase products in a fluidized bed reactor. The concrete process flow is as follows: gaseous solid-phase reaction occurs between chloromethane and silicon powder in a fluidized bed reactor to generate mixed monomer methyl chlorosilane; the gas phase product generated from the reaction is removed of dust by means of cyclone; the separated solid is discharged into a dust box after being sent into a dust collector; After being separated with cyclone separator, the reaction gas that contains a small amount of dust enters the venture scrubber, where mixed methyl chlorosilane monomer is used as cleaning solution for wet dust removal; the gas that has been removed of dust enters the fractional condenser after passing through a gas evaporator and buffer tank; the cooled product enters degassing column, and finally methyl chlorosilane is obtained.
Some companies also use the combination of dry bag-type dust collector and water washing to remove the solid-phase dust from gas mixture. However, traditional cyclone dust collector and bag-type dust collector cannot completely remove the small-sized dust from gas mixture, and so it needs to use washing method to further remove dust from gas mixture. As a result, the entire process is complicated, and dust removal by water washing will consume a great amount of industrial water, and wastewater release will impact the environment.
An organic chlorosilane wet dust removal process has been announced in China's patent number CN1438226A. This process replaces the traditional dry dust removal process with a continuous wet dust removal method that uses organic chlorosilane as a cleaning solution; there are no dust removal steps of cyclone separator or bag-type collector during an entire process. However, the slurry of this dust removal method contains about 60% of organochlorosilane; in this case, it is difficult to extract the solid matter from the scullery, and the consumption of organic chlorosilane is high.
A kind of dry dust removal method and unit for organic chlorosilane gas is introduced in China's patent number CN101148453A. In this method, the DIA-SCHUMALITH 10-20 porcelain filter element produced by PALL Company is used to remove dust from dust-containing gas mixture, and the purified organosilane gas mixture gets into the next working procedure. DIA-SCHUMALITH 10-20 filter element is formed by way of binding porcelain and carborundum. Large-pored carborundum crystal lattice is used as a rigid and stable structure to support film; the film is the part that really plays filtering role, and is consisted of multi-aluminum andalusite, with thick of 100-200 μm and bore diameter of about 10 μm. However, this method is of terminal-type filtering method, and filter cake tends to accumulate on film surface, this would cause flow to rapidly decrease, and filtration resistance to increase, the frequent backwash for maintaining flow brings very high stress on the strength of film.